Videodermoscopy of healthy forearm skin (Figure, A and B), healthy mucosa of the lower lip (Figure, C and D), a nodular basal cell carcinoma of the nose (Figure, E and F), and a psoriatic plaque ofthe groin (Figure, G and H) was performed at ×150 magnification with a device that emits visible light at 700 to 400 nm (Figure, A, C, E, and G) and at a filtered wavelength of 390 to 410 nm (peak, 400 nm), representing the upper limit of visible light (Figure, B, D, F, and H). The peak absorption of hemoglobin is approximately 400 nm; therefore, the 400-nm light is nearly completely absorbed, and hemoglobin-containing vessels are seen as black (no light reflection). The morphological appearance of the vessels, which is punctiform, hairpinlike, arborizing, and bushylike, respectively, is representative of the pattern that is seen in similar cases. As shown, the 400-nm light source allows a more definitive visualization of the superficial vascular pattern in terms of vessel size and details, with enhancement of small vessels that are not visible with normal light. Definitive evaluation of vascular patterns is a useful tool in the diagnosis and therapeutic follow-up of a large variety of skin disorders, and the use of a videodermoscopic system equipped with a 400-nm light source represents an important imaging advancement in the evaluation of skin microcirculation, by improving vessel details and enhancing vessel contrast compared with standard videodermoscopic imaging.
Lacarrubba F, Potenza MC, Micali G. Enhanced Videodermoscopic Visualization of Superficial Vascular Patterns on Skin Using a 390- to 410-nm Light. Arch Dermatol. 2012;148(2):276. doi:10.1001/archdermatol.2011.692